1. Field of the Invention
This invention relates to processes and apparatuses for closing packaging sheaths made of flexible material, particularly tubular bags, by means of a U-shaped closing clip,
2. Related Art
In apparatuses known, e.g., from German Patent Specifications 15 11 725 and 12 85 350 the gathered end portion of the packaging sheath is laterally inserted into the receiving space between the guideways for the two legs of the closing clip and the female die is fixed in its closing position at the end of the guideway for the clip. The apparatus disclosed in German Patent Specification 15 11 725 can be used in a vertical or horizontal orientation, e.g., for closing vertically suspended, filled bags. However when vertically suspended filled bags have been closed, the bags must suitably be pulled out of the closing machine because a removal through the feed opening would be difficult. Further, the lateral feed opening must be relatively narrow because otherwise the guideway for feeding one of the legs of the closing clip would have to be interrupted for an excessively long distance so that the closing clip might be tilted. If the feed opening is relatively narrow, the removal of the closed bag opposite to the feeding direction will involve great difficulty. On the other hand, the removal of the filled and closed bag in a downward direction requires a complicated manipulation.
It is also known (DE-A2 20 45 229) that the female die can be laterally moved to a position in front of the guideway for the clip so that the female die will be swung in at the same time as the gathering arms. In that case the gathering arms and the female die are moved against the tightly filled package so that the difficulty discussed hereinbefore cannot arise.
It is also known (Published German Application 21 61 593) that an end portion of a packaging sheath can be closed in that said end portion is placed into a receiving fork and is engaged by a clip-guiding guideway of a packaging machine as that guideway descends onto the end portion of the sheath, the female die is then pivotally moved by means of a lever to a position in front of the guideway for the clip and the punch is then operated to close the closing clip on the female die around the gathered neck of the sheath. In that case considerable closing forces (about 300 kg) act via the female die on the system for imparting a pivotal movement to and for locking the female die and this results in considerable wear, which gives rise to inaccuracies.
For this reason it is an object of the invention to provide processes and apparatuses which are of the kind described hereinabove and in which the forces acting on the female die during the closing operation are not transmitted to the mechanism for actuating the female die but are directly transmitted to the body of the machine.